Various conventional industrial processes are used for the manufacture or refinement of various products and materials. For example, the aggregate industry uses industrial processes to convert raw quarry materials into finished products such as gravel, crushed rock, asphalt, or concrete materials. Typically, these conventional industrial processes involve conveyors, which transfer raw material through various processing stations as part of an industrial system. Each station performs various refinements to the materials moving through the system on the conveyor. Conventional industrial systems use various techniques for monitoring the particle size of bulk materials traveling through the system on a conveyor or the like.
One typical prior art method for providing size distribution measurements of bulk material moving on a conveyor involves using an automated or manual sampling procedure. This prior art method involves analyzing a physical sample of the conveyed raw material in a laboratory setting where screen sieve analysis is used to determine the size of particles in the material sample. In addition, there are a number of conventional techniques for physically characterizing the size and shape or reflectance of materials traveling on a conveyor in an industrial process. These conventional techniques, which are used primarily for sorting operations, employ a variety of different techniques. For example, U.S. Pat. No. 3,357,557 discloses a technique for using reflected light as a means of determining the flatness of semiconductor chips. In U.S. Pat. No. 4,057,146, beans, grain, and similar produce are sorted by size and color analysis as a result of light being reflected from the produce. Similarly, various types of ores have been sorted as a function of light reflectance. In this regard, U.S. Pat. Nos. 3,097,744; 3,901,388; and 3,977,526 are representative examples. In addition, other conventional ore sorters use lasers as a light source such as the system disclosed in U.S. Pat. Nos. 3,545,610 and 4,122,952. Other conventional ore sorters use infrared light as the light source such as U.S. Pat. No. 4,236,640.
Various conventional automated particle analysis systems are commercially available for rapidly determining the grain size distribution of unbound aggregates. These conventional systems provide a faster alternative to standard sieve analysis. These conventional machines capture and analyze digital images of the aggregate particles on a conveyor stream to determine size gradation. Such conventional particle analysis systems include, for example, the VDG-40 Video Grader developed by Emaco, Ltd. of Canada; the Computer Particle Analyzer (CPA) developed by W. F. Tyler and Terry Reckart; the OptiSizer, PFDA5400, by Micromeritics Instrument Corp.; Particle Size Distribution Analyzer (PSDA), by Buffalo Wire Works Company; and the Particle Parameter Measurement System (PPMS), by Scientific Industrial Automation Pty. Limited.
Each of these material analysis systems uses various techniques to obtain information about objects or materials being processed in an industrial system. However, the conventional systems have been unable to use this information to monitor and control the operation of the overall industrial process. Because the conventional material analysis systems have typically been added on to existing industrial systems, are normally remote from the existing process equipment, such as located in a laboratory, there has not been any focus placed on the use of the information gathered by these systems for monitoring or controlling the industrial process as a whole.
In addition, the conventional systems have been unable to obtain accurate information about coarse and fine particles and objects simultaneously and use that information to monitor or control the industrial process as a whole.
Thus, a control feedback system and method for industrial processes using automated particle or object analysis is needed.